The present invention relates to cleaning vehicles and in particular to a steering mechanism for a cleaning vehicle which conjointly turns or pivots all of the wheels of the cleaning vehicle when a change in vehicle direction is desired.
Cleaning vehicles such as rider sweepers, rider scrubbers, and combination sweeping and scrubbing machines need to be very maneuverable in order to do an effective job in cleaning floors or other surfaces around obstacles and in tight locations within factories or other types of facilities. A typical three-wheel cleaning vehicle is configured such that the third wheel, which is longitudinally offset from the other two wheels of the vehicle, is located at the front of the vehicle and is selectively pivotal, while the other two wheels are non-pivotal, such that the cleaning vehicle steers from the front. The third wheel can alternatively be located behind the other two wheels at the rear of the vehicle and consequently the vehicle will steer from the rear. With just one wheel being pivotal to steer the vehicle, the vehicle is limited in maneuverability when it is positioned close to objects, such as when sweeping and scrubbing along a wall. When a rear-steering vehicle is being used to clean along the edge of a wall, the vehicle must be inched away from the wall well in advance of encountering the upcoming obstruction in order to steer the vehicle away from the wall when the obstruction is encountered. Otherwise, in a rear-steering vehicle, a sharp turn will shift the back end of the vehicle up against the wall creating interference and possibly damaging the vehicle and the wall.
When the third wheel that steers the vehicle is located at the front of the vehicle, such as on a typical direct-throw style sweeper, the wheel is placed directly in the path of the debris and limits the effectiveness of this type of sweeper. Often, to maximize maneuverability on a three-wheeled vehicle, the third wheel is also the drive wheel as well as the steering wheel. Thus, the power that propels the vehicle is transferred through just one wheel to the support surface. When just one drive wheel is used, having sufficient traction between the drive wheel and the support surface is a concern and a problem, especially in connection with scrubbing machines where the drive wheel encounters wet surfaces created by the cleaning vehicle.
The present all-wheel steering mechanism powers two front wheels for improved traction over a one-wheel powered design. The steering mechanism connects the two front wheels and a third rear wheel such that each wheel conjointly turns or pivots when a change in direction of the vehicle is desired. When the cleaning vehicle of the present invention with the all-wheel steering mechanism is scrubbing or sweeping close to a wall and makes a turn, the vehicle may be pulled away from the wall by conjointly turning both front wheels in a first direction, such that the front end of the vehicle moves away from the wall, and conjointly turning the rear wheel in a second opposite direction, such that the back end of the vehicle moves toward the wall. This provides a quick break-away from the wall or other obstruction without creating any interference. The third wheel is located at the rear of the vehicle behind the two front drive wheels. Therefore the sweeping mechanism of the cleaning vehicle, which is a direct-throw style, has no wheels in the debris path causing interference. As the two front drive wheels are powered and are located ahead of the scrubbing system, they will typically be located on a dry surface to provide enhanced traction and driving control.